2 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 * NB: these functions have been "upgraded", the deprecated versions (which
12 * are compatibility wrappers using these functions) are in rsa_depr.c. -
17 * RSA low level APIs are deprecated for public use, but still ok for
20 #include "internal/deprecated.h"
24 #include "internal/cryptlib.h"
25 #include <openssl/bn.h>
26 #include <openssl/self_test.h>
27 #include "prov/providercommon.h"
28 #include "rsa_local.h"
30 static int rsa_keygen_pairwise_test(RSA
*rsa
, OSSL_CALLBACK
*cb
, void *cbarg
);
31 static int rsa_keygen(OPENSSL_CTX
*libctx
, RSA
*rsa
, int bits
, int primes
,
32 BIGNUM
*e_value
, BN_GENCB
*cb
, int pairwise_test
);
35 * NB: this wrapper would normally be placed in rsa_lib.c and the static
36 * implementation would probably be in rsa_eay.c. Nonetheless, is kept here
37 * so that we don't introduce a new linker dependency. Eg. any application
38 * that wasn't previously linking object code related to key-generation won't
39 * have to now just because key-generation is part of RSA_METHOD.
41 int RSA_generate_key_ex(RSA
*rsa
, int bits
, BIGNUM
*e_value
, BN_GENCB
*cb
)
43 if (rsa
->meth
->rsa_keygen
!= NULL
)
44 return rsa
->meth
->rsa_keygen(rsa
, bits
, e_value
, cb
);
46 return RSA_generate_multi_prime_key(rsa
, bits
, RSA_DEFAULT_PRIME_NUM
,
50 int RSA_generate_multi_prime_key(RSA
*rsa
, int bits
, int primes
,
51 BIGNUM
*e_value
, BN_GENCB
*cb
)
54 /* multi-prime is only supported with the builtin key generation */
55 if (rsa
->meth
->rsa_multi_prime_keygen
!= NULL
) {
56 return rsa
->meth
->rsa_multi_prime_keygen(rsa
, bits
, primes
,
58 } else if (rsa
->meth
->rsa_keygen
!= NULL
) {
60 * However, if rsa->meth implements only rsa_keygen, then we
61 * have to honour it in 2-prime case and assume that it wouldn't
62 * know what to do with multi-prime key generated by builtin
66 return rsa
->meth
->rsa_keygen(rsa
, bits
, e_value
, cb
);
70 #endif /* FIPS_MODULE */
71 return rsa_keygen(rsa
->libctx
, rsa
, bits
, primes
, e_value
, cb
, 0);
75 static int rsa_multiprime_keygen(RSA
*rsa
, int bits
, int primes
,
76 BIGNUM
*e_value
, BN_GENCB
*cb
)
78 BIGNUM
*r0
= NULL
, *r1
= NULL
, *r2
= NULL
, *tmp
, *prime
;
79 int n
= 0, bitsr
[RSA_MAX_PRIME_NUM
], bitse
= 0;
80 int i
= 0, quo
= 0, rmd
= 0, adj
= 0, retries
= 0;
81 RSA_PRIME_INFO
*pinfo
= NULL
;
82 STACK_OF(RSA_PRIME_INFO
) *prime_infos
= NULL
;
85 unsigned long error
= 0;
88 if (bits
< RSA_MIN_MODULUS_BITS
) {
89 ok
= 0; /* we set our own err */
90 RSAerr(0, RSA_R_KEY_SIZE_TOO_SMALL
);
94 /* A bad value for e can cause infinite loops */
95 if (e_value
!= NULL
&& !ossl_rsa_check_public_exponent(e_value
)) {
96 RSAerr(0, RSA_R_PUB_EXPONENT_OUT_OF_RANGE
);
100 if (primes
< RSA_DEFAULT_PRIME_NUM
|| primes
> rsa_multip_cap(bits
)) {
101 ok
= 0; /* we set our own err */
102 RSAerr(0, RSA_R_KEY_PRIME_NUM_INVALID
);
110 r0
= BN_CTX_get(ctx
);
111 r1
= BN_CTX_get(ctx
);
112 r2
= BN_CTX_get(ctx
);
116 /* divide bits into 'primes' pieces evenly */
120 for (i
= 0; i
< primes
; i
++)
121 bitsr
[i
] = (i
< rmd
) ? quo
+ 1 : quo
;
125 /* We need the RSA components non-NULL */
126 if (!rsa
->n
&& ((rsa
->n
= BN_new()) == NULL
))
128 if (!rsa
->d
&& ((rsa
->d
= BN_secure_new()) == NULL
))
130 BN_set_flags(rsa
->d
, BN_FLG_CONSTTIME
);
131 if (!rsa
->e
&& ((rsa
->e
= BN_new()) == NULL
))
133 if (!rsa
->p
&& ((rsa
->p
= BN_secure_new()) == NULL
))
135 BN_set_flags(rsa
->p
, BN_FLG_CONSTTIME
);
136 if (!rsa
->q
&& ((rsa
->q
= BN_secure_new()) == NULL
))
138 BN_set_flags(rsa
->q
, BN_FLG_CONSTTIME
);
139 if (!rsa
->dmp1
&& ((rsa
->dmp1
= BN_secure_new()) == NULL
))
141 BN_set_flags(rsa
->dmp1
, BN_FLG_CONSTTIME
);
142 if (!rsa
->dmq1
&& ((rsa
->dmq1
= BN_secure_new()) == NULL
))
144 BN_set_flags(rsa
->dmq1
, BN_FLG_CONSTTIME
);
145 if (!rsa
->iqmp
&& ((rsa
->iqmp
= BN_secure_new()) == NULL
))
147 BN_set_flags(rsa
->iqmp
, BN_FLG_CONSTTIME
);
149 /* initialize multi-prime components */
150 if (primes
> RSA_DEFAULT_PRIME_NUM
) {
151 rsa
->version
= RSA_ASN1_VERSION_MULTI
;
152 prime_infos
= sk_RSA_PRIME_INFO_new_reserve(NULL
, primes
- 2);
153 if (prime_infos
== NULL
)
155 if (rsa
->prime_infos
!= NULL
) {
156 /* could this happen? */
157 sk_RSA_PRIME_INFO_pop_free(rsa
->prime_infos
, rsa_multip_info_free
);
159 rsa
->prime_infos
= prime_infos
;
161 /* prime_info from 2 to |primes| -1 */
162 for (i
= 2; i
< primes
; i
++) {
163 pinfo
= rsa_multip_info_new();
166 (void)sk_RSA_PRIME_INFO_push(prime_infos
, pinfo
);
170 if (BN_copy(rsa
->e
, e_value
) == NULL
)
173 /* generate p, q and other primes (if any) */
174 for (i
= 0; i
< primes
; i
++) {
183 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
186 BN_set_flags(prime
, BN_FLG_CONSTTIME
);
190 if (!BN_generate_prime_ex(prime
, bitsr
[i
] + adj
, 0, NULL
, NULL
, cb
))
193 * prime should not be equal to p, q, r_3...
194 * (those primes prior to this one)
199 for (j
= 0; j
< i
; j
++) {
207 prev_prime
= sk_RSA_PRIME_INFO_value(prime_infos
,
210 if (!BN_cmp(prime
, prev_prime
)) {
215 if (!BN_sub(r2
, prime
, BN_value_one()))
218 BN_set_flags(r2
, BN_FLG_CONSTTIME
);
219 if (BN_mod_inverse(r1
, r2
, rsa
->e
, ctx
) != NULL
) {
220 /* GCD == 1 since inverse exists */
223 error
= ERR_peek_last_error();
224 if (ERR_GET_LIB(error
) == ERR_LIB_BN
225 && ERR_GET_REASON(error
) == BN_R_NO_INVERSE
) {
231 if (!BN_GENCB_call(cb
, 2, n
++))
237 /* calculate n immediately to see if it's sufficient */
239 /* we get at least 2 primes */
240 if (!BN_mul(r1
, rsa
->p
, rsa
->q
, ctx
))
243 /* modulus n = p * q * r_3 * r_4 ... */
244 if (!BN_mul(r1
, rsa
->n
, prime
, ctx
))
247 /* i == 0, do nothing */
248 if (!BN_GENCB_call(cb
, 3, i
))
253 * if |r1|, product of factors so far, is not as long as expected
254 * (by checking the first 4 bits are less than 0x9 or greater than
255 * 0xF). If so, re-generate the last prime.
257 * NOTE: This actually can't happen in two-prime case, because of
258 * the way factors are generated.
260 * Besides, another consideration is, for multi-prime case, even the
261 * length modulus is as long as expected, the modulus could start at
262 * 0x8, which could be utilized to distinguish a multi-prime private
263 * key by using the modulus in a certificate. This is also covered
264 * by checking the length should not be less than 0x9.
266 if (!BN_rshift(r2
, r1
, bitse
- 4))
268 bitst
= BN_get_word(r2
);
270 if (bitst
< 0x9 || bitst
> 0xF) {
272 * For keys with more than 4 primes, we attempt longer factor to
273 * meet length requirement.
275 * Otherwise, we just re-generate the prime with the same length.
277 * This strategy has the following goals:
279 * 1. 1024-bit factors are efficient when using 3072 and 4096-bit key
280 * 2. stay the same logic with normal 2-prime key
283 if (!BN_GENCB_call(cb
, 2, n
++))
290 } else if (retries
== 4) {
292 * re-generate all primes from scratch, mainly used
293 * in 4 prime case to avoid long loop. Max retry times
303 /* save product of primes for further use, for multi-prime only */
304 if (i
> 1 && BN_copy(pinfo
->pp
, rsa
->n
) == NULL
)
306 if (BN_copy(rsa
->n
, r1
) == NULL
)
308 if (!BN_GENCB_call(cb
, 3, i
))
312 if (BN_cmp(rsa
->p
, rsa
->q
) < 0) {
321 if (!BN_sub(r1
, rsa
->p
, BN_value_one()))
324 if (!BN_sub(r2
, rsa
->q
, BN_value_one()))
327 if (!BN_mul(r0
, r1
, r2
, ctx
))
330 for (i
= 2; i
< primes
; i
++) {
331 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
332 /* save r_i - 1 to pinfo->d temporarily */
333 if (!BN_sub(pinfo
->d
, pinfo
->r
, BN_value_one()))
335 if (!BN_mul(r0
, r0
, pinfo
->d
, ctx
))
340 BIGNUM
*pr0
= BN_new();
345 BN_with_flags(pr0
, r0
, BN_FLG_CONSTTIME
);
346 if (!BN_mod_inverse(rsa
->d
, rsa
->e
, pr0
, ctx
)) {
350 /* We MUST free pr0 before any further use of r0 */
355 BIGNUM
*d
= BN_new();
360 BN_with_flags(d
, rsa
->d
, BN_FLG_CONSTTIME
);
362 /* calculate d mod (p-1) and d mod (q - 1) */
363 if (!BN_mod(rsa
->dmp1
, d
, r1
, ctx
)
364 || !BN_mod(rsa
->dmq1
, d
, r2
, ctx
)) {
369 /* calculate CRT exponents */
370 for (i
= 2; i
< primes
; i
++) {
371 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
372 /* pinfo->d == r_i - 1 */
373 if (!BN_mod(pinfo
->d
, d
, pinfo
->d
, ctx
)) {
379 /* We MUST free d before any further use of rsa->d */
384 BIGNUM
*p
= BN_new();
388 BN_with_flags(p
, rsa
->p
, BN_FLG_CONSTTIME
);
390 /* calculate inverse of q mod p */
391 if (!BN_mod_inverse(rsa
->iqmp
, rsa
->q
, p
, ctx
)) {
396 /* calculate CRT coefficient for other primes */
397 for (i
= 2; i
< primes
; i
++) {
398 pinfo
= sk_RSA_PRIME_INFO_value(prime_infos
, i
- 2);
399 BN_with_flags(p
, pinfo
->r
, BN_FLG_CONSTTIME
);
400 if (!BN_mod_inverse(pinfo
->t
, pinfo
->pp
, p
, ctx
)) {
406 /* We MUST free p before any further use of rsa->p */
413 RSAerr(0, ERR_LIB_BN
);
420 #endif /* FIPS_MODULE */
422 static int rsa_keygen(OPENSSL_CTX
*libctx
, RSA
*rsa
, int bits
, int primes
,
423 BIGNUM
*e_value
, BN_GENCB
*cb
, int pairwise_test
)
428 * Only multi-prime keys or insecure keys with a small key length will use
429 * the older rsa_multiprime_keygen().
431 if (primes
== 2 && bits
>= 2048)
432 ok
= ossl_rsa_sp800_56b_generate_key(rsa
, bits
, e_value
, cb
);
435 ok
= rsa_multiprime_keygen(rsa
, bits
, primes
, e_value
, cb
);
436 #endif /* FIPS_MODULE */
439 pairwise_test
= 1; /* FIPS MODE needs to always run the pairwise test */
441 if (pairwise_test
&& ok
> 0) {
442 OSSL_CALLBACK
*stcb
= NULL
;
443 void *stcbarg
= NULL
;
445 OSSL_SELF_TEST_get_callback(libctx
, &stcb
, &stcbarg
);
446 ok
= rsa_keygen_pairwise_test(rsa
, stcb
, stcbarg
);
448 ossl_set_error_state(OSSL_SELF_TEST_TYPE_PCT
);
449 /* Clear intermediate results */
450 BN_clear_free(rsa
->d
);
451 BN_clear_free(rsa
->p
);
452 BN_clear_free(rsa
->q
);
453 BN_clear_free(rsa
->dmp1
);
454 BN_clear_free(rsa
->dmq1
);
455 BN_clear_free(rsa
->iqmp
);
468 * For RSA key generation it is not known whether the key pair will be used
469 * for key transport or signatures. FIPS 140-2 IG 9.9 states that in this case
470 * either a signature verification OR an encryption operation may be used to
471 * perform the pairwise consistency check. The simpler encrypt/decrypt operation
472 * has been chosen for this case.
474 static int rsa_keygen_pairwise_test(RSA
*rsa
, OSSL_CALLBACK
*cb
, void *cbarg
)
477 unsigned int ciphertxt_len
;
478 unsigned char *ciphertxt
= NULL
;
479 const unsigned char plaintxt
[16] = {0};
480 unsigned char decoded
[256];
481 unsigned int decoded_len
;
482 unsigned int plaintxt_len
= (unsigned int)sizeof(plaintxt_len
);
483 int padding
= RSA_PKCS1_PADDING
;
484 OSSL_SELF_TEST
*st
= NULL
;
486 st
= OSSL_SELF_TEST_new(cb
, cbarg
);
489 OSSL_SELF_TEST_onbegin(st
, OSSL_SELF_TEST_TYPE_PCT
,
490 OSSL_SELF_TEST_DESC_PCT_RSA_PKCS1
);
492 ciphertxt_len
= RSA_size(rsa
);
493 ciphertxt
= OPENSSL_zalloc(ciphertxt_len
);
494 if (ciphertxt
== NULL
)
497 ciphertxt_len
= RSA_public_encrypt(plaintxt_len
, plaintxt
, ciphertxt
, rsa
,
499 if (ciphertxt_len
<= 0)
501 if (ciphertxt_len
== plaintxt_len
502 && memcmp(ciphertxt
, plaintxt
, plaintxt_len
) == 0)
505 OSSL_SELF_TEST_oncorrupt_byte(st
, ciphertxt
);
507 decoded_len
= RSA_private_decrypt(ciphertxt_len
, ciphertxt
, decoded
, rsa
,
509 if (decoded_len
!= plaintxt_len
510 || memcmp(decoded
, plaintxt
, decoded_len
) != 0)
515 OSSL_SELF_TEST_onend(st
, ret
);
516 OSSL_SELF_TEST_free(st
);
517 OPENSSL_free(ciphertxt
);